1. Yared and Luke are wrapping presents. Yared is able to wrap presents at a constant rate of 3 presents every 15 min. Luke is able to wrap presents at a constant rate of 5 presents every 20 min. Each boy has 20 presents to wrap, and the boys started wrapping presents at the same time. (a) How many presents will Yared still need to finish wrapping when Luke has finished wrapping all 20 of his presents? Explain.
(b) What percent of his presents will Yared still need to wrap when Luke has finished wrapping presents? Explain.
(Can someone please explain this to me)

Answer for Question A) Yared will still need to wrap 4 more presents when Luke is finished.

Explanation for Question A) Yared will still need to wrap 4 more presents because he has a slower rate of wrapping his presents. Yared wraps 3 presents every 15 minutes (or you can write it as 4 presents every 20 minutes) and Luke wraps 5 presents for every 20 minutes. So Luke is faster at wrapping than Yared. Therefore Yared will have 4 more presents to finish when Luke is done.

Answer for Question B) Yared will still need to wrap 20% of his presents when Luke finishes.

Explanation for Question B) It is the same as the other one except you just have to make it a percentage. So 16/20 as a percentage is 20%.

Sorry if I can't explain very well, but those are the correct answers!

Hope this helps you!!

c.

step-by-step explanation:

because first you have to add the 4x, 9x, and the 7x together and you get 20x and then you add the last numbers up and you get 5and then you put the subtraction sign in there and that's how you get the answer.

explanation:

infrared radiation has wavelength in the range between 700 nm and 1 mm. lets' convert these values into scientific notation, keeping in mind that:

let's start from the lower value, we have:

(we moved the dot two places to the left, so we increased the exponent by 2 units, from -9 to -7)

the higher value is:

so, the range of wavelength of infrared radiation is: